A “cubesat,” also known as a cube satellite, a “nano-sat”, or a “micro-sat”, is a type of miniaturized satellite. A cubesat is typically measured in volumes of “1 U” or “1 Unit”, which is exactly one litre, or a 10 cm cube with a mass of no more than 1.33 kilograms. The 1 U size is commonly clustered together in 2 U, 3 U, 6 U, or 12 U configurations. Cubesats are very small compared to conventional spacecraft, and are therefore constrained for volume.
A star tracker, or a star camera, is a device used in spacecraft attitude control. Star trackers typically include an optical system, a radiance detector, and signal processing electronics, which can be used to measure the positions of stars. The optical system of a star tracker may include a lens assembly and a light baffle. Star trackers require high sensitivity, and may become confused by light contamination from the sun or the earth, drowning out the low signal from faint stars. Light baffles may therefore be used to reduce noise from scattered light in the star tracker telescope.
Light baffles typically form a cone or cylinder of around the field of view of a lens assembly to block stray light from entering the lens from outside the field of view. Blades, baffles, or ridges that point inwards from the main cone of a light baffle help reduce scattering from stray light.
Light baffle designs, which must be large enough to allow a star tracker to detect very faint stars in the presence of the very bright sunlight, typically extend 5-40 cm in length. On a cubesat, prior designs have included a fixed light baffle, which may cover a large portion of the 10 cm length of a 1 U unit.
It is an object of the present invention to provide a light baffle which overcomes the disadvantages of the prior art, or at least provides a useful alternative.